The present invention relates to a biochip reading apparatus and a biochip reading method for making an analysis based on distribution of the light quantity of fluorescence generated at a site on a biochip.
A method using a biochip is known as a method for identifying a biopolymer such as DNA. For example, in the case of identifying DNA, a DNA probe having the known base sequence is fixed to each of the sites of a biochip and DNA having the complementary base sequence is bound to each of the sites by hybridization. The amount of binding can be recognized as the light quantity of fluorescence by labeling the bound DNA with a fluorescent molecule.
[Non-Patent Reference 1]
Touru Makino, Kyouichi Kano, Journal “Optics”, Optical Technology in Life Science “DNA Analysis and Optical Technology”, Volume 28, No. 10 (1999), (Aggregate Corporation) Society Committee of Applied Physics, Japan Optical Society, 1999, p. 549-552
The light quantity is measured using a dedicated reading apparatus. It is necessary to detect a position of a site in order to measure the light quantity of each of the sites. A method for detecting a position of a site includes a method for being irradiated with excitation light and using fluorescence of each of the sites and a method for illuminating a biochip by white illumination and checking a position of a site.
However, in the former method, it is difficult to detect a site with dark fluorescence and also brightness of a site varies depending on the number of fluorescent molecules, so that the light quantity varies every site and an accurate position cannot be detected. Also, there is a problem that color fading occurs in fluorescence by being irradiated with excitation light.
Also, in the latter method, a wavelength of excitation light is included in white light, so that fluorescent molecules of a site are excited and color fading of fluorescence is inevitable. Also, the fluorescent molecules of each of the sites are excited, so that brightness of each of the sites varies depending on the number of fluorescent molecules and it is difficult to detect an accurate position.